Java Key Concepts

Java Key Concepts


Final Keyword:

- The `final` keyword is used to define constants. Once a value is assigned to a `final` variable, it cannot be changed.

Changing Data Types (Typecasting):

- You can change a data type by casting it. For example, converting a `double` to an `int` removes the decimal part.

Using the + Operator:

- The `+` operator serves two purposes in Java: it adds numbers and concatenates (joins) strings.

Declaring Multiple Variables:

- You can declare multiple variables of the same type in a single line, separated by commas.



Program Example:

Code:


public class JavaKeyConceptsExample {

    public static void main(String[] args) {


        // Final keyword

        final int MAX_HEIGHT = 100;

        System.out.println("Final variable (MAX_HEIGHT): " + MAX_HEIGHT);


        
        // Typecasting

        double myDouble = 9.78;

        int myInt = (int) myDouble;  // Casting double to int

        System.out.println("Typecasted double to int: " + myInt);


        
        // + operator for addition and concatenation

        int a = 5;

        int b = 10;

        System.out.println("Sum of a and b: " + (a + b));

        String firstName = "John";

        String lastName = "Doe";

        System.out.println("Full Name: " + firstName + " " + lastName);


        
        // Multiple variable declaration

        int x = 100, y = 200, z = 300;

        System.out.println("Multiple Variables: " + x + ", " + y + ", " + z);

    }

}


OUTPUT